ISOLATION, IDENTIFICATION AND VIRULENCE GENE PROFILING OF ESCHERICHIA COLI O157: H7 IN RETAIL DONER KEBABS, IRAN

Most illnesses caused by Escherichia coliO157:H7 have been associated with eating undercooked, contaminated meat. In this study, a number of 200 cooked beef doner kebab samples from different restaurants across cities of Tehran and Mashhad were analyzed. After enrichment, selective plating and biochemical tests, the DNA from suspected colonies were extracted. Three multiplex polymerase chain reaction (PCR) assays to confirm the isolates as E.coliO157:H7 and the presence of virulence factors were performed. Specific primers for cH7 and rfbO157 genes in the first and for stx1 and stx2 genes in the second m-PCR were used. The third m-PCR performed using specific primers for eaeA and EhlyA genes. From 25 nonsorbitol-fermenting isolates, 21 isolates confirmed as E.coliO157:H7. The results of third m-PCR showed 12 isolates harboring the EhlyA gene, three isolates the eaeA gene and three isolates harboring both the EhlyA and eaeA genes. Practical ApplicationsThe presence of Escherichia coliO157:H7 in cooked beef doner kebabs could be considered a serious public health hazard. These three multiplex PCR assay are a suitable method for rapid identification of E.coliO157:H7 virulence genes.